İşaret zamirleri — demonstratives
Where English has only 'this' and 'that', Turkish has three demonstratives: bu (this — near the speaker), şu (that — mid-distance, often something you're physically pointing at), and o (that — far away, or already known to both speakers). The same words are both pronouns and adjectives. Bu kitap = 'this book'. Bu, kitap (with a comma) = 'This is a book'. The third-person pronoun o that you learned in lesson 2 is the same word as the far demonstrative — context decides whether it means 'he/she/it' or 'that'.
The three-way distinction
Bu points at something close to the speaker — what you're holding, pointing at within reach. bu kalem = this pen (in my hand). Şu is a halfway pointer — the thing across the room that you're looking at or gesturing toward. şu masa = that table (over there). O is far or out of sight: o şehir = that city. O is also the default when the thing has already been mentioned: Bir kedi var. O çok güzel = 'There's a cat. It's very pretty'.
Demonstrative as adjective
Just place bu/şu/o before the noun, with no other change. bu adam = this man. şu çay = that tea (over there). o ev = that house. The noun stays singular when the demonstrative does — even if you mean 'these books' you say bu kitaplar with the demonstrative still in the singular form.
Demonstrative as pronoun ('this is')
Drop the noun and add the third-person 'is' (which is normally invisible) and you get a complete sentence. Bu kitap = 'this book'. Bu, kitap or just Bu kitap. with the right intonation = 'This is a book'. In writing, a comma helps disambiguate. With negation: Bu kitap değil = 'This isn't a book' (more on değil below).
Asking 'What is this?' and 'Who is this?'
Bu ne? = 'What is this?'. Şu ne? = 'What's that (over there)?'. O ne? = 'What's that (far)?'. Same pattern with kim (who): Bu kim? = 'Who is this?'. O kim? = 'Who is that?'. The answer is just the noun: Bu kitap = 'This is a book'. O Mehmet = 'That's Mehmet'.
The negator: değil
Turkish has a separate word değil for negating noun/adjective sentences. (You can't make var/yok or 'to be' negative the same way — they have their own forms.) Bu kitap değil = 'This is not a book'. O öğretmen değil, doktor = 'He's not a teacher, he's a doctor'. Değil even takes personal endings: Ben öğretmen değilim = 'I am not a teacher'. We'll use it lightly here.
